HABIT : large, seasonally dormant herbs, tuber subglobose, subterranean, with annular leaf scars, growing continuously and not renewed with each growing period. LEAF : solitary, large. PETIOLE : long, aculeate, sheath very short. BLADE : trisect, primary divisions pinnatifid or bipinnatifid to pinnatisect, ultimate (distal) lobes mostly truncate to shallowly bifid, sessile to decurrent, proximal lobes acute-acuminate; primary lateral veins of ultimate lobes pinnate, forming irregular submarginal collective vein or running into margin, higher order venation reticulate. INFLORESCENCE : solitary, appearing before leaf. PEDUNCLE : aculeate, very short, much shorter than petiole. SPATHE : large, somewhat resembling the horn of a euphonium, unconstricted, bright yellow, dark purple within and at mouth of tube, tube convolute, fleshy, obconic, blade very broad, thinner, with flaring, auriculate margins, fornicate. SPADIX : very short, sessile, female zone subcylindric, male zone cylindric, obtuse, subequal to or longer than female, fertile to apex (P. gabunensis) or with appendix covered with sterile flowers (P. buettneri). FLOWERS : unisexual, perigone absent. MALE FLOWER : 2-5-androus, stamens free, subprismatic, compressed, anthers sessile, connective thick, broad, overtopping thecae, thecae oblong, long, lateral, dehiscing by apical pore. POLLEN : extruded in strands, inaperturate, ellipsoid-oblong, very large (mean 106 µm., range 93-114 µm.), exine psilate to slightly scabrous. STERILE MALE FLOWERS : composed of subprismatic, free staminodes. FEMALE FLOWER : ovary globose to broadly ellipsoid, sometimes compressed, 2(-3)-locular, ovules 1 per locule, anatropous, funicle short, placenta axile at base of septum, style attenuate to cylindric, narrower than ovary, stigma thick, 2(-3)-lobed, concave centrally. BERRY : unknown. SEED : unknown.
Large, seasonally dormant geophyte; leaf solitary; petiole prickly; leaf blade dracontioid, ultimate leaf lobes mostly truncate to shallowly bifid, submarginal collective vein irregular or absent, fine venation reticulate; spathe large, lower part a convolute tube, upper part very broad with flaring auricled margins; spadix fertile to apex or with terminal appendix of staminodes; flowers unisexual, perigone absent. Differs from Anchomanes in very short peduncle and 2-locular ovary.